Ha, yes, I've done that at https://gigablast.com/ . The biggest problems now are the following: 1) Too hard to spider the web. Gatekeeper companies like Cloudflare (owned in part by Google) and Cloudfront make it really difficult for upstart search engines to download web pages. 2) Hardware costs are too high. It's much more expensive now to build a large index (50B+ pages) to be competitive. I believe my algorithms…
Do you have a cost estimate? Also could you be more selective in indexing, e.g. by having users requests sites to be crawled.